Fiber and ferrule assemblies are typically formed by securing a glass fiber within a ceramic ferrule by any of various methods, but one of the most common is by use of an epoxy-based adhesive. The ceramic of the ferrule constitutes a relatively tough material with excellent dimensional stability and generally somewhat customizable CTE. While use of epoxy is generally an inexpensive approach, there are significant disadvantages, including the difficulty of achieving repeatable quality in the adhesive bond, typically requiring careful inspection, cold storage, precise mixing, degassing, and careful dispensing of the epoxy. Limited pot life after mixing and undesirably long curing times after application are additional disadvantages of epoxy.
The present disclosure provides according to one aspect, a pre-terminated optical fiber assembly with a ferrule 14 having front and rear opposed faces and at least one fiber bore defined longitudinally therethrough. A glass optical fiber is disposed within the at least one fiber bore, and the fiber is fused to the ferrule at a location at least 1 mm deep inside the bore. The ferrule 14 is desirably composed of an inorganic composite material, the composite comprising a material gradient from at least 75% by volume of a first inorganic material to at least 75% by volume of second inorganic material in the radially inward direction, where the first inorganic material has a fracture toughness of at least 1 MPa·m1/2, and the second inorganic material has a softening point of no greater than 1000° C., desirably no greater than 900° C.
According to another aspect, the present disclosure also provides a method of fabricating an optical fiber connector assembly, the method comprising: providing an optical fiber; providing a ferrule having front and rear opposed faces and at least one fiber bore defined longitudinally therethrough; positioning the fiber within the at least one fiber bore; and fusing the fiber to the ferrule at a location at least 1 mm deep inside the at least one fiber bore by irradiating the fiber and ferrule with laser energy. The step of providing a ferrule desirably comprises providing a ferrule comprised of an inorganic composite material, the composite comprising a material gradient from at least 75% by volume of a first inorganic material to at least 75% by volume of second inorganic material in the radially inward direction, with the first inorganic material having a fracture toughness of at least 1 MPa·m1/2 and the second inorganic material having a softening point of no greater than 1000° C.
Variations of the methods and devices of the present disclosure are described in the text below and with reference to the figures, described in brief immediately below.